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#1 2015-03-04 03:57:37

marshmellow
Contributor
From: US
Registered: 2013-06-10
Posts: 2,302

ata5577 passwords and locking bits.

Are there any known weaknesses in the ata5577 password protection mode?

or wake with password mode?

or block locking bits?

(Other than snooping the writing of the tag.)

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#2 2015-03-04 09:56:47

iceman
Administrator
Registered: 2013-04-25
Posts: 9,507
Website

Re: ata5577 passwords and locking bits.

By the simple one I understood from it,  is the block lock bits is wrong then the password block could be read.

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#3 2015-03-04 14:10:18

marshmellow
Contributor
From: US
Registered: 2013-06-10
Posts: 2,302

Re: ata5577 passwords and locking bits.

Not sure about that, but I know if the config block is set wrong it (to output 7 blocks) it will transmit all its memory including the block used as a password.  But that is why the spec docs tell you not to set that to 7 if you use the password mode.

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#4 2015-03-04 14:45:00

iceman
Administrator
Registered: 2013-04-25
Posts: 9,507
Website

Re: ata5577 passwords and locking bits.

yup, thats what I meant.
but how many hasn't gotten that wrong?

How about adding a pwd to a t55x7 tag and see if there are any timings issues, (like an oracle attack)  for wrong vs correct password.   If we can get that down,  it will be easy to bruteforce it.  Or what do you think?

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#5 2015-03-04 15:53:44

asper
Contributor
Registered: 2008-08-24
Posts: 1,409

Re: ata5577 passwords and locking bits.

This is a good idea iceman.

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#6 2015-03-04 15:59:09

marshmellow
Contributor
From: US
Registered: 2013-06-10
Posts: 2,302

Re: ata5577 passwords and locking bits.

So the idea is it would take a different amount of time to reject the bad password for each correct byte guessed correctly?

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#7 2015-03-04 17:03:43

iceman
Administrator
Registered: 2013-04-25
Posts: 9,507
Website

Re: ata5577 passwords and locking bits.

Yes, that would be the assumption we'll be trying to verify.  Somewhere the line that a bad password gets rejected faster OR slower than a correct one.

We'll need to time it..  but then t55x7 might not respond to a faulty pwd command but silently discard it.

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#8 2015-03-04 18:31:02

marshmellow
Contributor
From: US
Registered: 2013-06-10
Posts: 2,302

Re: ata5577 passwords and locking bits.

The tag may not respond on a bad password but there may be an interruption to the data stream it is always outputting (except wake on password configured cards.)

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#9 2015-03-04 18:33:10

marshmellow
Contributor
From: US
Registered: 2013-06-10
Posts: 2,302

Re: ata5577 passwords and locking bits.

However, I have no clue how we could measure the time accurate enough to tell anyway, it would no doubt be very small.

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#10 2015-03-04 19:44:01

iceman
Administrator
Registered: 2013-04-25
Posts: 9,507
Website

Re: ata5577 passwords and locking bits.

well, research, or the wild frontier!

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